Hepatitis C is recognized as a chronic viral disease of the liver. Although drugs targeting the liver are in wide use and have shown efficacy, toxicity and other side effects have limited their usefulness. Inhibitors of hepatitis C virus (HCV) are useful to limit the establishment and progression of infection by HCV as well as in diagnostic assays for HCV.
The compound (S)-isopropyl 2-((S)-(((2R,3R,4R,5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-4-fluoro-3-hydroxy-4-methyltetrahydrofuran-2-yl)methoxy)(phenoxy)phosphorylamino)propanoate, designated herein as Compound I, also known as Sofosbuvir, is an effective anti-HCV agent and is described in International Publication Numbers WO 2008/121634 and WO 2011/123654, and in U.S. Pat. Nos. 7,964,580 and 8,618,076. While certain crystalline forms of Compound I have been reported, Compound I was not heretofore known in the crystalline forms described herein.